Infrared light adjustment method and position detection system

ABSTRACT

An adjustment method for adjusting the direction of infrared light projected so that infrared light to pass over a displayed image from a projection device that is rotatable with orthogonal first and second axes as axes of rotation, the method including: arranging the projection device such that the plane containing the first axis and a line perpendicular to the upper edge or lower edge of the displayed image is orthogonal to the plane in which the displayed image is displayed; displaying a first image representing a first target on the line; and rotating the projection device with the second axis as the axis of rotation such that the irradiation position of the infrared light upon an indicator in the first image, in which is displayed a captured image, coincides with the position of the first target on the first image.

TECHNICAL FIELD

The present invention relates to an infrared light adjustment method anda position detection system, and for example, relates to an adjustmentmethod and position detection system for adjusting the direction ofinfrared light that is used for detecting the position of an indicatorthat indicates a portion of a displayed image.

BACKGROUND ART

There are many examples of the introduction of electronic blackboardsystems, such as for the purposes of adopting IT (InformationTechnology) in the classroom or raising efficiency in businessconferences.

Patent Document 1 discloses a projector system that can be used as anelectronic blackboard system.

The projector system described in Patent Document 1 includes aprojector, an electronic stylus, and a stylus manipulation detectionmeans. The electronic stylus is used to indicate a portion of an image(hereinbelow referred to as a “displayed image”) that the projector hasdisplayed on a projection surface such as a wall and to add charactersor pictures to a portion of the displayed image. The electronic stylussupplies a signal such as an infrared ray that accords with jottingmanipulation. The stylus-tip manipulation detection means detects thesignal that is supplied from the electronic stylus with respect to aportion of the displayed image that was indicated by the electronicstylus. The projector adds characters or pictures that accord with thedetection result of the pen-tip manipulation detection means to theportion of the displayed image that was indicated by the electronicstylus.

LITERATURE OF THE PRIOR ART Patent Documents

Patent Document 1: Japanese Unexamined Patent Application PublicationNo. 2014-167498

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In the projector system described in Patent Document 1, an electronicstylus was used to indicate a portion of a displayed image and to addcharacters or pictures. As a result, when the electronic stylusmalfunctions, the projector system becomes unable to recognize theportion of the displayed image that is indicated by the electronicstylus.

A method is therefore desired that enables recognition, on the systemside, that a portion of a displayed image has been indicated even in acase of using, for example, an indicator such as the human hand orfinger or a pointer instead of an electronic stylus.

As the technology for realizing this method, a technology can beconsidered in which infrared light is projected from a projection unitso as to pass over a projected image; in which an image is captured in astate in which the indicator that is pointing to a portion of the imageon the displayed image is irradiated by the infrared light; and in whichthe position of the indicator on the displayed image is recognized onthe basis of the captured image.

FIG. 1 shows an example of a projection unit that is used for realizingthe above-described technology.

Projection unit 1 projects infrared light L1 such that infrared light L1passes over displayed image 4.

FIG. 2 shows an example of projection unit 1. Projection unit 1 includesa plurality of laser light sources 1 a that emit, for example, infraredlight, and a plurality of cylindrical lenses (hereinbelow also referredto as “prisms”) 1 b that have a one-to-one correspondence with laserlight sources 1 a.

The plurality of laser light sources 1 a are arranged in an arc. Eachlaser light source la supplies infrared light (laser light) toward theoutside of the arc. Each cylindrical lens 1 b reads the infrared lightthat is supplied from corresponding laser light source 1 a in thedirection of arrow B.

In order to recognize the position of the indicator on displayed image 4by using the above-described technology, the plane that containsprogression region L2 of infrared light L1 is preferably set parallel todisplayed image 4 (display surface) such that infrared light L1 does notcome into contact with displayed image 4 (the display surface).

FIG. 3 shows the state in which infrared light L1 comes into contactwith projection surface 6 on which displayed image 4 is projected. Inthis case, infrared light L1 does not reach indicator 5 that is pointingto, of displayed image 4, portion 41 that is not covered by infraredlight L1. As a result, indicator 5 cannot be detected. Displayed image 4in the figure is given thickness for the sake of explanation. Inaddition, indicator 5 is, for example, a human hand or finger or apointer. Indicator 5 is not limited to a human hand or finger or pointerand can be altered as appropriate.

FIG. 4 shows an example of a state in which the plane that containsprogression region L2 is not parallel to projection surface 6. In theexample shown in FIG. 4, irradiation location 5 a is not close toportion 5 b of indicator 5 that is pointing to displayed image 4 and isat a location separated from portion 5 b. As a result, the portion ofdisplayed image 4 that is indicated by indicator 5 and irradiationlocation 5 a no longer correspond in the captured image that wasgenerated by imaging unit 2 and the accuracy of position detectiondecreases. Imaging unit 2 uses light of a wavelength band that containsinfrared light and visible light to capture displayed image 4 andgenerate a captured image.

In order to thus recognize the position of the indicator on thedisplayed image by using the technology described hereinabove, the planethat contains progression region L2 of infrared light L1 is preferablyset parallel to displayed image 4.

However, infrared light is not visible to the human eye, and it istherefore difficult for the unaided human to set the plane that containsprogression region L2 of infrared light L1 parallel to displayed image 4(the display surface). The issue therefore arises of the need for amethod of easily adjusting the setting of the plane that containsprogression region L2 of infrared light L1 parallel to displayed image 4(the display surface).

It is an object of the present invention to provide an infrared lightadjustment method and position detection system that can solve theabove-described problem.

Means for Solving the Problem

The infrared light adjustment method of the present invention is aninfrared light adjustment method for adjusting the direction of infraredlight that is projected so as to pass over a displayed image from arotatable projection device that is rotatable with each of a first axisand a second axis that is orthogonal to the first axis as axes ofrotation, the method including steps of:

-   arranging the projection device such that the plane that contains    the first axis and a line that is perpendicular to the upper edge or    lower edge of the displayed image is orthogonal to the plane in    which the displayed image is displayed;-   displaying a first image that represents a first target on the line    as the displayed image;-   rotating the projection device with the second axis as the axis of    rotation such that the position of irradiation of the infrared light    upon the indicator in the displayed image, in which is represented a    captured image that captures a state of the indicator that points to    the first target being irradiated by the infrared light, coincides    with the position of the first target in the displayed image;-   displaying, as the displayed image in place of the first image, a    second image that represents a second target at a location that is    different from the line; and-   rotating the projection device with the first axis as the axis of    rotation such that the irradiation position of the infrared light    upon the indicator in the displayed image, in which is represented a    captured image that captures a state of the infrared light    irradiating the indicator that points to the second target,    coincides with the position of the second target in the displayed    image.

The position detection system of the present invention includes:

-   a projection unit that is rotatable with each of a first axis and a    second axis that is orthogonal to the first axis as the axes of    rotation, that is arranged such that the plane that contains the    first axis and a line that is perpendicular to the upper edge or    lower edge of a displayed image is orthogonal to the plane in which    the displayed image is displayed, and moreover, that projects    infrared light so as to pass over the displayed image;-   an imaging unit that captures an image of the state in which    infrared light is irradiated upon an indicator that points to a    portion of the displayed image to generate a captured image; and-   a determination unit that determines the position of the indicator    on the displayed image on the basis of the captured image.

Effect of the Invention

The present invention enables easy adjustment of setting a plane thatcontains the progression region of infrared light parallel to adisplayed image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows progression region L2 of infrared light L1.

FIG. 2 shows an example of projection unit 1.

FIG. 3 shows the state in which infrared light L1 comes into contactwith projection surface 6.

FIG. 4 shows an example of a state in which the plane that containsprogression region L2 is not parallel to projection surface 6.

FIG. 5 shows projector system 200 of an exemplary embodiment of thepresent invention.

FIG. 6 is a schematic side view of projector system 100.

FIG. 7 shows an example of infrared light projection device 8.

FIG. 8 shows an example of manipulation unit 10 x and adjustment unit 10y.

FIG. 9 shows an example of manipulation unit 10 x and adjustment unit 10y.

FIG. 10A is a view for describing the operation when dial 10 b isrotated.

FIG. 10B is a view for describing the operation when dial 10 b isrotated.

FIG. 11A is a view for describing the operation when dial 10B isrotated.

FIG. 11B is a view for describing the operation when dial 10 b isrotated.

FIG. 12 shows an example of control device 9, imaging unit 2, projector7, and infrared light projection device 8.

FIG. 13 shows an example of calibration image 11.

FIG. 14 shows an example of captured image 2 a 1.

FIG. 15 is a view for describing an example of adjustment that uses dial10 b and dial 10 i.

FIG. 16 shows an example of pitching adjustment image 12.

FIG. 17A shows an example of a state in which target 12 a is touched byindicator 5 such as a finger.

FIG. 17B shows an example of an image that shows the relation betweenthe detection coordinates and the first target coordinates.

FIG. 18 is a view for describing the movement of rolling axis R thataccords with the rotation of dial 10 b.

FIG. 19 shows an example of rolling adjustment image 13.

FIG. 20 shows an example of the state in which target 13 a is touched byindicator 5 such as a finger.

FIG. 21 is a view for describing the movement of pitching axis P thataccords with the rotation of dial 10 i.

BEST MODE FOR CARRYING OUT THE INVENTION

An exemplary embodiment of the present invention is next described withreference to the accompanying drawings.

FIG. 5 shows projector system 100 in which the adjustment method of theexemplary embodiment of the present invention has been applied. FIG. 6is a schematic side view of projector system 100 shown in FIG. 5. InFIGS. 5 and 6, the same reference numbers are given to components havingthe same configuration as shown in FIGS. 1-4.

Explanation is first presented regarding projector system 100 in whichthe adjustment method of an exemplary embodiment of the presentinvention has been applied.

Projector system 100 includes imaging unit 2, projector 7, infraredlight projection device 8, and control device 9. Projector 7 displays onprojection surface 6 displayed image 4 that accords with a picturesignal received from control device 9. Infrared light projection device8 is an example of a projection device and position detection auxiliarydevice. Infrared light projection device 8 projects infrared light L1.

FIG. 7 shows an example of infrared light projection device 8.

Infrared light projection device 8 includes projection unit 1,manipulation unit 10 x, and adjustment unit 10 y. The user manipulatesmanipulation unit 10 x. Adjustment unit 10 y changes the orientation ofprojection unit 1 according to the manipulation of manipulation unit 10x.

In the present exemplary embodiment, the direction of infrared light L1that is projected from projection unit 1 is adjusted by the manipulationof manipulation unit 10 x.

FIG. 8 shows an example of projection unit 1 and manipulation unit 10 xand adjustment unit 10 y. FIG. 9 is a schematic view of theconfiguration shown in FIG. 8. In FIG. 9, support units 10 f and 10 nthat are shown in FIG. 8 have been omitted for the purpose ofsimplifying the explanation.

Of the constituent elements shown in FIGS. 8 and 9, dials 10 b and 10 iare examples of the manipulation unit. Of the constituent elements shownin FIGS. 8 and 9, the portion that is made up constituent elements thatdiffer from projection units 10 g and 10 h and dials 10 b and 10 i is anexample of adjustment unit 10 y. In addition, manipulation unit 10 x andadjustment unit 10 y are not limited to the configuration shown in FIG.8 and can be altered as appropriate.

Substrate 10 a can be moved with support point 10 a 1 (see FIG. 9) as acenter.

Projection units 10 g and 10 h are each examples of projection unit 1.Projection units 10 g and 10 h each spread the light supplied from alaser light source by a prism and emit infrared light in fan-shapedform. The infrared light projected from each of projection units 10 gand 10 h covers the entire displayed image. The reason for providing twoprojection units such as projection units 10 g and 10 h is to ensure theintensity of the infrared light.

Axis R that passes through support point 10 a 1 and adjustment point 10a 2 is hereinbelow referred to as “rolling axis R” (see FIG. 9). Inaddition, axis P that passes through support point 10 a 1 and that isorthogonal to rolling axis R is referred to as “pitching axis P” (seeFIG. 9).

Projection units 10 g and 10 h are secured to the edge of substrate 10 athat is on the opposite side from adjustment point 10 a 2 with respectto support point 10 a 1 such that progression region L2 of infraredlight L1, rolling axis R, and pitching axis P all exist in the sameplane. Projection units 10 g and 10 h project infrared light L1 in thedirection opposite from substrate 10 a.

FIGS. 10A and 10B are schematic views for describing the operation whendial 10 b is rotated. In FIGS. 10A and 10B, support units 10 f and 10 nhave been omitted in the interest of simplifying the explanation.

When dial 10 b is turned, toothed wheel 10 c that is fixed to dial 10 brotates. When toothed wheel 10 c rotates, toothed wheel 10 d and shaft10 e that is fixed to toothed wheel 10 d also rotate. Male threading isprovided on shaft 10 e. The male threading on shaft 10 e meshes withfemale threading of support unit (such as a nut) 10 f (see FIG. 8). As aresult, the positions of shaft 10 e and toothed wheel 10 d change inaccordance with the direction of rotation of shaft 10 e. With themovement of one end 10 e 1 of shaft 10 e, rolling axis R rotates withpitching axis P that contains support point 10 a 1 as the center (seeFIGS. 9 and 10A). Accordingly, rolling axis R rotates with pitching axisP as the center in accordance with the direction of rotation of dial 10b. The orientation of projection unit 1 that is secured to substrate 10a therefore changes.

FIGS. 11A and 11B are schematic views for describing the operation whendial 10 i is turned. In FIGS. 11A and 11B, support units 10 f and 10 nare omitted in the interest of simplifying the explanation.

When dial 10 i is turned, toothed wheel 10 j that is secured to dial 10i rotates. When toothed wheel 10 j rotates, toothed wheel 10 k and shaft10 m that is secured to toothed wheel 10 k also rotate. Male threadingis provided on shaft 10 m. The male threading of shaft 10 m meshes withthe female threading of support unit 10 n that has a fixed position (seeFIG. 8). The positions of shaft 10 m and toothed wheel 10 k thereforechange according to the direction of rotation of shaft 10 m. Supportunit 10 p that supports substrate 10 a (see FIG. 9) therefore movesalong guide groove 10 q 1 of guide unit 10 q with the movement of oneend 10 m 1 of shaft 10 m. Accordingly, pitching axis P rotates withrolling axis R that contains support point 10 a 1 as the center inaccordance with the direction of rotation of dial 10 i. The orientationof projection unit 1 that is secured to substrate 10 a thereforechanges.

Control device 9 shown in FIG. 5 controls projector system 100. Controldevice 9 is, for example, a PC (Personal Computer). Control device 9 isnot limited to a PC and can be altered as appropriate.

FIG. 12 shows imaging unit 2, projector 7, infrared light projectiondevice 8, and an example of control device 9.

Control device 9 includes control unit 91, display unit 92, and picturesignal output unit 93. Control unit 91 controls the operation of controldevice 9. For example, control unit 91 performs an operation thataccords with the angle of divergence between displayed image 4 and theplane that contains progression region L2 of infrared light L1. Displayunit 92 displays a variety of information. Picture signal output unit 93supplies a picture signal to projector 7.

The adjustment operation in which the plane that contains progressionregion L2 of infrared light L1 is made parallel or substantiallyparallel to displayed image 4 (projection surface 6) is next described.

Picture signal output unit 93 of control device 9 first supplies apicture signal to projector 7. Projector 7, and upon receiving thepicture signal, displays displayed image 4 that accords with the picturesignal on projection surface (for example, a screen) 6.

Infrared light projection device 8 is next set such that, when viewedfrom a direction perpendicular to projection surface 6, rolling axis R(first axis) of adjustment unit 10 y overlies centerline 4 a ofdisplayed image 4 (see FIG. 5). Centerline 4 a is an example of the linethat is perpendicular to the upper edge or lower edge of displayed image4. In the present exemplary embodiment, centerline 4 a passes throughthe center of displayed image 4. As a result, infrared light projectiondevice 8 is arranged such that the plane that contains rolling axis Rand centerline 4 a of displayed image 4 is orthogonal to the plane inwhich displayed image 4 is displayed.

The user manipulates control device 9 to activate calibration softwarethat has been installed in control device 9.

Control unit 91 activates calibration software in accordance with thismanipulation. Control unit 91 executes the following process inaccordance with the calibration software.

Control unit 91 supplies a picture signal for calibration from picturesignal output unit 93 to projector 7. The picture signal for calibrationindicates an image (hereinbelow referred to as a “calibration image”)for causing coordinates, that have been set in an image that accordswith a picture signal that is recognized by control unit 91, tocorrespond with coordinates in displayed image 4 that is displayed incaptured image 2 a.

FIG. 13 shows an example of calibration image 11.

Calibration image 11 includes reference point 11 a that indicates theupper left of displayed image 4, reference point 11 b that indicates thelower right of displayed image 4, reference point 11 c that indicatesthe upper right of displayed image 4, and reference point 11 d thatindicates the lower left of displayed image 4.

Next, imaging unit 2 captures calibration image 11 to generate capturedimage 2 a 1 that accords with calibration image 11.

FIG. 14 shows an example of captured image 2 a 1.

Imaging unit 2 supplies captured image 2 a 1 to control device 9.

Control unit 91 of control device 9 causes the coordinates of theposition of reference point 11 a shown in captured image 2 a 1 tocorrespond to the coordinates of the position of the upper left ofdisplayed image 4. Control unit 91 further causes the coordinates of theposition of reference point 11 b shown in captured image 2 a 1 tocorrespond to the coordinates of the position of the lower right ofdisplayed image 4. Control unit 91 further causes the coordinates of theposition of reference point 11 c indicated in captured image 2 a 1 tocorrespond to the coordinates of the position of the upper right ofdisplayed image 4. Finally, control unit 91 causes the coordinates ofthe position of reference point 11 d indicated in captured image 2 a 1to correspond to the coordinates of the position of the lower left ofdisplayed image 4. In this way, the coordinates in displayed image 4represented by captured image 2 a correspond to the coordinates in animage (an image that accords with a picture signal) that is recognizedby control unit 91.

Infrared light projection device 8 projects infrared light L1 in a fanshape from outside the upper portion of displayed image 4 such thatinfrared light L1 passes over displayed image 4. At this time, thesurface that forms progression region L2 of infrared light L1 ispreferably parallel or substantially parallel to displayed image 4.

However, because infrared light L1 is not visible to the human eye, itis difficult for a person to visually set the plane that formsprogression region L2 of infrared light L1 parallel to or substantiallyparallel to displayed image 4.

However, the present exemplary embodiment assists in the adjustment ofsetting the plane that forms progression region L2 of infrared light L1parallel or substantially parallel to displayed image 4.

In the present exemplary embodiment, the inclination adjustment ofprogression region L2 that takes pitching axis P of infrared lightprojection device 8 as the axis of rotation is referred to as “pitchingdirection adjustment.” The inclination adjustment of progression regionL2 that takes rolling axis R of infrared light projection device 8 asthe axis of rotation is referred to as the “rolling directionadjustment.”

The orientation of the plane that forms progression region L2 (anglewith respect to projection surface 6) is determined by the position ofthree points on the plane that forms progression region L2.

In the present exemplary embodiment, support point 10 a 1 is used as onepoint of these three points (refer to FIG. 9). Adjustment point 10 a 2and adjustment point 10 a 3 are used as the remaining two points (referto FIG. 9).

The position of adjustment point 10 a 2 can be adjusted by rotating dial10 b. The position of adjustment point 10 a 3 can be adjusted byrotating dial 10 i.

Support point 10 a 1 and rolling axis R are positioned on the centerlineof infrared light projection device 8. Pitching axis P is arranged so asto pass through support point 10 a 1 and be orthogonal to rolling axisR.

In the present exemplary embodiment, the angle of the plane that formsprogression region L2 of infrared light L1 is adjusted by the user whomanipulates (adjusting) dial 10 b and dial 10 i in the order of firstmanipulating dial 10 b and then manipulating dial 10 i.

Dial 10 b corresponds to pitching direction adjustment. Rolling axis Rrotates with pitching axis P as the axis of rotation according torotation of dial 10 b. As a result, the angle of rolling axis R isadjusted according to the rotation of dial 10 b.

Dial 10 i corresponds to rolling angle adjustment. Pitching axis Protates with rolling axis R as the axis of rotation according to therotation of dial 10 i.

In the present exemplary embodiment, from among an adjustment operationthat uses dial 10 b and an adjustment operation that uses dial 10 i, anadjustment operation that uses dial 10 b is performed before anadjustment operation that uses dial 10 i.

An adjustment operation that uses dial 10 b is performed before anadjustment operation that uses dial 10 i because the adjustment of theangle of the plane that forms progression region L2 is easier. Thispoint is explained below.

If the pitching direction adjustment is completed first, rolling axis Ris parallel to projection surface 6 (the screen).

The rolling direction adjustment is next implemented. In this case,pitching axis P is rotated with rolling axis R that is parallel toprojection surface 6 as the axis of rotation.

As a result, the plane that forms progression region L2 of infraredlight L1 can be set parallel to projection surface 6 (displayed image4).

In order to complete the adjustment of the plane in which progressionregion L2 is formed in two steps, dial 10 b and dial 10 i aremanipulated in the order of first manipulation dial 10 b and thenmanipulating dial 10 i as described hereinabove.

The adjustment operation that uses dial 10 b and dial 10 i is nextdescribed.

FIG. 15 is a view for describing the adjustment operation that uses dial10 b and dial 10 i. The pitching direction adjustment begins whencontrol unit 91 receives an instruction to begin the adjustment processthat uses dial 10 b and dial 10 i from an input unit (not shown) (StepS201).

In Step S201, control unit 91 supplies a picture signal for pitchingdirection adjustment from picture signal output unit 93 to projector 7.The picture signal for pitching direction adjustment represents apitching adjustment image for performing the pitching directionadjustment.

FIG. 16 shows an example of pitching adjustment image 12.

Pitching adjustment image 12 has target 12 a that is an example of thefirst target and instruction 12 b.

Target 12 a is located in the lower portion of centerline 12 c ofpitching adjustment image 12. As a result, target 12 a is located oncenterline 12 c in the vicinity of the side that is opposite to the sideof infrared light projection device 8. In addition, centerline 12 c isan example of the line that is perpendicular to the upper edge or loweredge of pitching adjustment image 12 that is an example of displayedimage 4. In the present exemplary embodiment, centerline 12 c passesthrough the center of pitching adjustment image 12.

Instruction 12 b requires “Touch target 12 a of the lower portion of thescreen center with an indicator such as a finger (an obstruction).”

Upon receiving the picture signal for pitching direction adjustment,projector 7 displays pitching adjustment image 12 on projection surface6 as displayed image 4.

The user places indicator 5 such as his or her finger in contact withtarget 12 a in accordance with instruction 12 b that is displayed inpitching adjustment image 12.

FIG. 17A shows an example of the state in which target 12 a is beingtouched by indicator 5 such as a finger.

When target 12 a is touched by indicator 5 such as a finger, infraredlight L1 is irradiated and diffused upon indicator 5.

Imaging unit 2 captures an image of the state in which indicator 5, suchas a finger, is in contact with target 12 a to generate captured image 2a. In other words, imaging unit 2 captures an image of the diffusedinfrared light. Imaging unit 2 supplies captured image 2 a to controlunit 91.

Control unit 91 determines irradiation location 5 a on displayed image4, that is displayed in captured image 2 a, as the position of indicator5 on displayed image 4.

Control unit 91 next displays on display unit 92 the relation betweenthe position of indicator 5 on displayed image 4 and the position oftarget 12 a on pitching adjustment image 12 (displayed image 4) that isspecified from the picture signal for pitching direction adjustment. Forexample, control unit 91 displays on display unit 92 the coordinates ofthe position of indicator 5 on displayed image 4 (hereinbelow referredto as the “detected coordinates”) and the coordinates of the position oftarget 12 a on pitching adjustment image 12 (hereinbelow referred to as“first target coordinates”).

FIG. 17B shows an example of an image that represents the relation ofthe detected coordinates and the first target coordinates.

When the detected coordinates coincide with the first targetcoordinates, control unit 91 displays on display unit 92 firstinformation that indicates matching of the coordinates (for example, theinformation “The detected coordinates have coincided with target 12 a”).The display of the first information means that the pitching directionadjustment has been completed.

Until the first information is displayed, the user continues to touchtarget 12 a with his or her finger and manipulate dial 10 b whilewatching the detected coordinates and the first target coordinates thatare displayed on display unit 92 to thus move and adjust the directionof infrared light L1 and cause the detected coordinates to coincide withthe first target coordinates. When the detected coordinates coincidewith with the first target coordinates, control unit 91 displays thefirst information (for example, “The detected coordinates have coincidedwith the first target coordinates”) on display unit 92 and the pitchingdirection adjustment is completed.

FIG. 18 is a view for describing the movement of rolling axis R thataccords with the rotation of dial 10 b. At the stage in which thepitching direction adjustment has been completed, rolling axis R is in astate of being parallel to projection surface 6 (refer to FIG. 18).

When the pitching direction adjustment has been completed (Step S202),the rolling direction adjustment begins (Step S203).

Because the pitching direction adjustment has been completed, rollingaxis R is in a state of being parallel to projection surface 6. In StepS203, pitching axis P is also made parallel to projection surface 6 byrotating pitching axis P with rolling axis R as the axis of rotation.

In Step S203, control unit 91 supplies a picture signal for rollingdirection adjustment from picture signal output unit 93 to projector 7.The picture signal for rolling direction adjustment indicates a rollingadjustment image for performing the rolling direction adjustment.

FIG. 19 shows an example of rolling adjustment image 13.

Rolling adjustment image 13 has target 13 a that is an example of thesecond target and instruction 13 b.

Target 13 a is located in the lower right corner (the lower left corneris also possible) of rolling adjustment image 13. As a result, target 13a is located in the vicinity of, of the sides that demarcate rollingadjustment image 13 that is an example of a displayed image, a side thatis parallel to centerline 12 c of rolling adjustment image 13 or that isin the vicinity of the end of a parallel side. Again, target 13 a islocated in the vicinity of the end of, of the sides that demarcaterolling adjustment image 13, a side that is parallel to centerline 12 c.Further, target 13 a is located in the vicinity of the end that isopposite to the side infrared light projection device 8 of, of the sidesthat demarcate rolling adjustment image 13, a side that is parallel tocenterline 12 c. Centerline 12 c of rolling adjustment image 13 is anexample of the line that is perpendicular to the upper edge or loweredge of rolling adjustment image 13 that is an example of displayedimage 4. In the present exemplary embodiment, centerline 12 c of rollingadjustment image 13 passes through the center of rolling adjustmentimage 13.

Instruction 13 b indicates “Touch target 13 a with an indicator 5 suchas a finger.”

Upon receiving the picture signal for rolling direction adjustment,projector 7 displays rolling adjustment image 13 on projection surface 6as displayed image 4.

The user places indicator 5 such as his or her finger in contact withtarget 13 a in accordance with instruction 13 b that is shown in rollingadjustment image 13.

FIG. 20 shows an example of the state in which indicator 5, such as afinger, is touching target 13 a.

When indicator 5 such as a finger is in contact with target 13 a,infrared light L1 is emitted and diffused upon indicator 5.

Imaging unit 2 captures an image of the state in which target 13 a is incontact with indicator 5, such as a finger, and generates captured image2 a. In other words, imaging unit 2 captures an image of the infraredlight that is diffused. Imaging unit 2 then supplies captured image 2 ato control unit 91.

Control unit 91 determines irradiation location 5 a on displayed image 4that is shown in captured image 2 a as the position of indicator 5 ondisplayed image 4.

Control unit 91 next displays on display unit 92 the relation betweenthe position of indicator 5 on displayed image 4 and the position oftarget 13 a on rolling adjustment image 13 (displayed image 4) that isspecified from the picture signal for rolling direction adjustment.

For example, control unit 91 displays on display unit 92 the coordinatesof the position of indicator 5 on displayed image 4 (the detectedcoordinates) and the coordinates of the position of target 13 a onrolling adjustment image 13 (hereinbelow referred to as the “secondtarget coordinates”).

When the detected coordinates coincide with the second targetcoordinates, control unit 91 displays on display unit 92 secondinformation (for example, the information that “The detected coordinateshave coincided with target 13 a”) that shows matching of thecoordinates. The display of the second information means that therolling direction adjustment has been completed.

Until the second information is displayed, the user continues to touchtarget 13 a with his or her finger and manipulates dial 10 i whilewatching the detected coordinates and the second target coordinates thatare displayed on display unit 92 to adjust the direction of infraredlight L1 and thus cause the detected coordinates to coincide with thesecond target coordinates. When the detected coordinates match with thesecond target coordinates, control unit 91 displays on display unit 92the second information (for example, the information that “The detectedcoordinates have coincided with target 13 a”), and the rolling directionadjustment is completed.

FIG. 21 is a view for describing the movement of pitching axis P thataccords with the rotation of dial 10 i.

At the stage in which the rolling direction adjustment has beencompleted, the pitching axis P is also in a state of being parallel toprojection surface 6 (see FIG. 21). As a result, the plane in whichprogression region L2 is formed is parallel to projection surface 6.

When the rolling direction adjustment has been completed (Step S204),control unit 92 completes the adjustment of the orientation ofprojection unit 1 (the adjustment of the orientation of the plane inwhich progression region L2 is formed).

As shown in the present exemplary embodiment, when rolling axis Roverlies centerline 4 a of displayed image 4, infrared light projectiondevice 8 can be set in a state in which there is no limitation upon thedistance (h) from the upper edge of displayed image 4 to infrared lightprojection device 8. As a result, infrared light projection device 8 maybe installed in a position that approaches the very upper edge ofdisplayed image 4. Alternatively, infrared light projection device 8 maybe installed at a distance from the upper edge of displayed image 4.This feature therefore increases the degree of freedom regarding screensthat can be used.

Target 13 a for the pitching direction adjustment may be at any positionon centerline 12 c without raising a problem. However, theimplementation of adjustment by using target 12 a that is at a moreremote location from the infrared light emission point of infrared lightprojection device 8 enables increased in accuracy. As a result, in thepresent exemplary embodiment, target 13 a is set in the vicinity of thelower edge of displayed image 4.

As with the rolling direction adjustment, the presence of target 13 a ata point close to the corner of displayed image 4 enables adjustment ofthe angle of the surface with greater accuracy than when target 13 a isat a point close to centerline 12 c. As a result, target 13 a is set inthe vicinity of a lower corner of displayed image 4 in the presentexemplary embodiment.

The action and effect of the present exemplary embodiment are nextdescribed.

In the present exemplary embodiment, adjustment support point 10 a 1 andadjustment axis (rolling axis) R are on the centerline of displayedimage 4 and infrared light projection device 8, and the other adjustmentaxis (pitching axis) P is arranged so as to pass through the sameadjustment support point 10 a 1 and be orthogonal to rolling axis R.

In this state, dial 10 b and dial 10 i are manipulated (adjusted) inthat order to adjust the angle of the plane in which infrared light L1is formed. Dial 10 b corresponds to the pitching direction adjustment,and the angle of rolling axis R is adjusted with pitching axis P as theaxis of rotation in accordance with the manipulation of dial 10 b. Dial10 i corresponds to the rolling direction adjustment, and the angle ofpitching axis P is adjusted with rolling axis R as the axis of rotationin accordance with the manipulation of dial 10 i.

As a result, adjustment for setting the plane that contains theprogression region of infrared light parallel to a displayed image canbe easily accomplished.

The reason for manipulating dial 10 b before dial 10 i is nextexplained.

If adjustment of the pitching direction is completed first, the wall(the screen surface) and rolling axis R are set in parallel. Theadjustment of the rolling direction is next implemented, but theadjustment of the right-left rotation direction is implemented with therolling axis that has been set parallel to the wall (the screen surface)as center. As a result, the plane of infrared light L1 that is parallelto the wall (the screen surface) can be set by manipulating as few astwo steps.

To complete adjustment in two steps, manipulation must be implemented inthe order of dial 10 b and dial 10 i as described here.

In the present exemplary embodiment, display unit 92 displays therelation between the position of the target on displayed image 4 and theposition of indicator 5 on displayed image 4 that was determined bycontrol unit 91.

As a result, by viewing the display on display unit 92, the user is ableto check the difference between two positions (the position of thetarget on displayed image 4 and the position of indicator 5 on displayedimage 4 that was determined by control unit 91) that are actually thesame position. This difference arises due to the inclination of theplane on which progression region L2 is formed with respect toprojection surface 6. As a result, by viewing the display on displayunit 92, the user is able to adjust the orientation of projection unit 1such that the orientation of projection unit 1 becomes the appropriateorientation.

Infrared light projection device 8 includes manipulation unit 10 x andadjustment unit 10 y that changes the orientation of projection unit 1in accordance with the manipulation of manipulation unit 10 x.

As a result, the user is able to adjust the orientation of projectionunit 1 such that the orientation of projection unit 1 is appropriate bymanipulating manipulation unit 10 x while viewing the display on displayunit 92.

In the present exemplary embodiment, the pitching direction adjustmentand the rolling direction adjustment are carried out by adjusting dial10 b and dial 10 i. As a result, the orientation of projection unit 1can be easily adjusted by the rotation of projection unit 1 around eachof two different axes of mutually different directions.

Modifications are next described.

In the above-described exemplary embodiment, a projection unit that hasa plurality of laser light sources 1 a and a plurality of cylindricallenses 1 b was used as projection unit 1, but projection unit 1 need notinclude a plurality of cylindrical lenses 1 b. In this case, a pluralityof laser light sources 1 a may be arranged such that adjacent laserlight sources 1 a are in contact. Alternatively, rather than using aplurality of laser light sources, infrared light may be projected in fanform by spreading the light supplied from a single laser light source bya prism.

Displayed image 4 is not limited to an image that is projected by aprojector and may be an image displayed by a display device such as anLCD (Liquid Crystal Display). In this case, the position of indicator 5that points to displayed image 4 can be detected even if, for example, adisplay device is used that lacks a touch panel.

In the exemplary embodiment described hereinabove, the configurationsshown in the drawings are merely examples, and the present invention isnot limited to these configurations.

Although the invention of the present application has been describedwith reference to an exemplary embodiment, the invention of the presentapplication is not limited to the above-described exemplary embodiment.The configuration and details of the invention of the presentapplication are open to various modifications within the scope of theinvention of the present application that will be clear to one ofordinary skill in the art.

EXPLANATION OF REFERENCE NUMBERS

-   100 position detection system-   1 projection unit-   1 a laser light source-   1 b cylindrical lens-   2 imaging unit-   4 displayed image-   5 indicator-   6 projection surface-   7 projector-   8 infrared light projection device-   9 control device-   10 x manipulation unit-   10 y adjustment unit-   10 a substrate-   10 a 1 support point-   10 a 2, 10 a 3 adjustment point-   10 b, 10 i dial-   10 c, 10 d, 10 j, 10 k toothed wheel-   10 e, 10 m shaft-   10 f, 10 n, 10 p support unit-   10 g, 10 h projection unit-   10 q guide unit-   10 q 1 guide groove-   L1 infrared light-   L2 progression region-   P pitching axis-   R rolling axis

1. An infrared light adjustment method for adjusting the direction ofinfrared light that is projected so that the light passes over adisplayed image from a rotatable projection device that is rotatablewith each of a first axis and a second axis that is orthogonal to thefirst axis as axes of rotation, the method comprising: arranging saidprojection device such that a plane that contains said first axis and aline that is perpendicular to the upper edge or lower edge of saiddisplayed image is orthogonal to a surface on which said displayed imageis displayed; displaying a first image that represents a first target onsaid line as said displayed image; rotating said projection device withsaid second axis as the axis of rotation such that the position ofirradiation of said infrared light upon an indicator in said displayedimage, in which is represented a captured image that captures a state ofsaid indicator that points to said first target being irradiated by saidinfrared light, coincides with the position of said first target in saiddisplayed image; displaying, as said displayed image in place of saidfirst image, a second image that represents a second target at alocation that is different from said line; and rotating said projectiondevice with said first axis as the axis of rotation such that theirradiation position of said infrared light upon said indicator in saiddisplayed image, in which is represented a captured image that capturesa state of an indicator that points to said second target beingirradiated by said infrared light, coincides with the position of saidsecond target in said displayed image.
 2. The infrared light adjustmentmethod as set forth in claim 1, wherein said line passes through thecenter of said displayed image.
 3. The infrared light adjustment methodas set forth in claim 1, wherein said first target is located on saidline in the vicinity of the side opposite to said projection device. 4.The infrared light adjustment method as set forth in claim 1, whereinsaid second target is located in the vicinity of, from among the sidesthat demarcate said display image, a side that is parallel to said line.5. The infrared light adjustment method as set forth in claim 4, whereinsaid second target is located in the vicinity of the end of, from amongthe sides that prescribe said displayed image, a side that is parallelto said line.
 6. The infrared light adjustment method as set forth inclaim 5, wherein said second target is located in the vicinity of theend that is opposite to said projection device-side of, from among sidesthat prescribe said displayed image, a side that is parallel to saidline.
 7. The infrared light adjustment method as set forth in claim 1,wherein displayed is the relation between, said irradiation position insaid displayed image, in which is displayed the state where an indicatorpointing to said first target and irradiated by said infrared light hasbeen captured in a captured image, and the position of said first targetin said displayed image.
 8. The infrared light adjustment method as setforth in claim 1, wherein displayed is the relation between, saidirradiation position in said displayed image, in which is displayed thestate where an indicator pointing to said second target and irradiatedby said infrared light has been captured in a captured image, and theposition of said second target in said displayed image.
 9. A positiondetection system comprising: a projection device that is rotatable witheach of a first axis and a second axis that is orthogonal to the firstaxis as the axes of rotation, that is arranged such that the plane thatcontains said first axis and a line that is perpendicular to the upperedge or lower edge of a displayed image is orthogonal to the plane inwhich said displayed image is displayed, and moreover, that projectslight so that said light passes over said displayed image; an imagingunit that captures an image of the state in which infrared light isirradiated upon an indicator that points to a portion of said displayedimage to generate a captured image; and a determination unit thatdetermines the position of said indicator on said displayed image on thebasis of said captured image.